Stem cells have shown promise as a treatment for brain injuries, but exactly how they work in improving function and repairing the brain has been unclear.

A team of researchers working with NeuroDevNet's Dr. Michael Fehlings has made strides in clarifying the mechanisms used by neural stem cells, considered the building blocks of the central nervous system, in restoring capacity in damaged brain pathways – particularly to the insulation surrounding nerves.

This insulation, called myelin, surrounds the connections between brain cells and helps speed up the transmission of the electrical impulses between them. In “Effects of Adult Neural Precursor-Derived Myelination on Axonal Function in the Perinatal Congenitally Dysmyelinated Brain: Optimizing Time of Intervention, Developing Accurate Prediction Modes, and Enhancing Performance,” published July 17 in the Journal of Neuroscience, the Fehlings team documented that injected stem cells built myelin in the brains of specially bred mice, and restored normal conductivity in damaged nerve cells.

“We injected the stem cells into the brains of mice that have a genetic mutation that results in a lack of myelin in the brain and spinal cord,” explained Dr. Crystal Ruff, a post-doctoral trainee working with Dr. Fehlings. “In this way, any myelin present after the stem cells were injected could be credited with confidence to the stem cell injection.”

The Fehlings team also recorded the speed of electrical impulses traveling along newly myelin-covered nerve fibres called axons. “We found that the axons that had regrown myelin insulation were showing a normal electrical profile,” said Dr. Ruff. “This indicates that the stem cells not only restored myelin, but that it was functioning as normal myelin would.”

“This demonstration of remyelination can have important clinical implications for a variety of neurodevelopmental conditions, including cerebral palsy (CP),” said lead researcher Dr. Michael Fehlings. Myelin damage is a key component of the brain injury seen in CP.

CP is the most common neurological disability in children - it occurs in 2 -2.5 out of every 1000 live births in developed countries. It reflects a brain injury that occurs before a baby is born, or around the time of birth.

Dr. Fehlings’ team also found that the mice injected with stem cells had improved resilience against injuries caused by lack of blood and oxygen to areas of the brain, known as ischemic insults. “This is another promising finding for CP,” added Dr. Ruff, “because brain injury resulting in a lack of blood and oxygen is a known cause of the disorder in childhood.”

“We pursued this research with the intent of producing results that will in time lead to therapies and treatments for CP,” she continued. “Restoring the myelin insulation around brain cells could be a reparative strategy for children with CP in the future – improving quality of life, and lessening disability.”

Dr. Fehlings’ remyelination work was funded by NeuroDevNet, with leveraged support from the Ontario Stem Cell Collaborative and Freedman Foundation (Dr. Ruff's post-doctoral fellow award) and the Halbert Chair in Neural Repair and Regeneration.